feat: no-constant-binary-expression report unnecessary nullish coales…

…cing operator like <expr1> ?? <non-nullish> ?? <expr2>
eslint · Jan 25, 2023 · 99d26bc · 99d26bc
1 parent d8c8ede
commit 99d26bc
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diff --git a/lib/rules/no-constant-binary-expression.js b/lib/rules/no-constant-binary-expression.js
@@ -45,6 +45,12 @@ function hasConstantNullishness(scope, node) {
             return (functionName === "Boolean" || functionName === "String" || functionName === "Number") &&
                 isReferenceToGlobalVariable(scope, node.callee);
         }
+        case "LogicalExpression": {
+            const isLeftConstant = hasConstantNullishness(scope, node.left);
+            const isRightConstant = hasConstantNullishness(scope, node.right);
+
+            return isLeftConstant || isRightConstant;
+        }
         case "AssignmentExpression":
             if (node.operator === "=") {
                 return hasConstantNullishness(scope, node.right);

diff --git a/tests/lib/rules/no-constant-binary-expression.js b/tests/lib/rules/no-constant-binary-expression.js
@@ -308,6 +308,12 @@ ruleTester.run("no-constant-binary-expression", rule, {
         { code: "x === /[a-z]/", errors: [{ messageId: "alwaysNew" }] },
 
         // It's not obvious what this does, but it compares the old value of `x` to the new object.
-        { code: "x === (x = {})", errors: [{ messageId: "alwaysNew" }] }
+        { code: "x === (x = {})", errors: [{ messageId: "alwaysNew" }] },
+
+        { code: "window.abc && false && anything", errors: [{ messageId: "constantShortCircuit" }] },
+        { code: "window.abc || true || anything", errors: [{ messageId: "constantShortCircuit" }] },
+        { code: "window.abc ?? 'non-nullish' ?? 'non-nullish'", errors: [{ messageId: "constantShortCircuit" }] },
+        { code: "window.abc ?? undefined ?? 'non-nullish'", errors: [{ messageId: "constantShortCircuit" }] },
+        { code: "window.abc ?? null ?? 'non-nullish'", errors: [{ messageId: "constantShortCircuit" }] }
     ]
 });